Diagnosis and monitoring systems, in which widely differing measurement variables are detected, assessed and stored, are being increasingly used for rail vehicle traffic. Inter alia, nowadays, in addition to the detection of the measurement variables of the drive and braking system, such as speeds, pressures, currents and voltages, which are required for operation of the rail vehicle, evermore measured values are being detected and stored for diagnosis of individual subsystems and components. The background in this case is that, in addition to ensuring the required functionality, better assessment of the wear state of components can be carried out, in order to better utilize their life.
In operation, a rail vehicle cannot be considered as an intrinsically closed system. This is because it is always influenced by the interaction with the respective track section. The environmental conditions and, of course, the track state, in particular adhesion in the wheel-rail contact or rail damage, can also be deduced by detection of various measurement variables in the vehicle, such as temperatures and accelerations. The knowledge of the position and therefore an association with a defined point on a track section are in this case directly assumed. At the moment, additional appliances are required for this purpose, which provide the required position information.
DE 102 33 527 B4 discloses a method for state diagnosis and monitoring of components of a rail vehicle, specifically wheel-set guide apparatuses, in which a position signal is estimated by evaluation of a currently measured acceleration signal and its double integration. This position signal is then used as a state variable for description of a coordinate of the current spatial position of the respective wheel set with respect to other components.
Furthermore EP 0 795 454 A1 discloses a method for a track-guided vehicle to locate itself, which is based on a correlation of acceleration spectra, determined on a position-dependent basis, of a current journey and a previous journey of the rail vehicle. In this case, the acceleration spectra represent a shaking profile for the track section, which is specific for the track section being travelled on and for a specific vehicle, and which is stored in an internal database in the form of a reference memory, and is correlated with currently measured acceleration spectra for position determination of the rail vehicle.
Furthermore, DE 601 18 501 D2 discloses a method and an apparatus for location of a rail vehicle, in which the speed of the vehicle on a rail section is determined at different times, and the current position of the rail vehicle is determined on the basis of a calculation, based on a specific algorithm using a database. In this case, in addition to geometric features, further data is stored in this database, which data has been recorded by measurement of an inertia variable from the vehicle previously travelling along that route.
DE 198 36 081 A1 discloses a technical solution for early identification of damage to rail vehicles. This state monitoring is based on an analysis of unusual noise or oscillations, which indicate damage to the rail vehicle. Sensors monitor those components which are subject to particular loads, such as wheel sets. The sensors produce current sound and oscillation values, which are compared with appropriate reference values in order to determine whether they are within predetermined limits. These reference values are stored in a reference memory, having previously been determined from a multiplicity of corresponding current measured values. The reference values apply to the respective track section points at which they were previously obtained. In order to create a reference between the current sound and oscillation values and the corresponding reference values, the reference values are called up repeatedly, to be precise whenever the sensors or vehicle components pass the relevant track section point, and generate the current sensor messages. The current sensor signals are associated with the corresponding reference signals by read pointers, which can be preselected in accordance with forward movement of the vehicle on the track section.
In the prior art, use is made of additional appliances, such as GPS receivers (GPS=Global Position System), in order to obtain the position information.
This prior art has the disadvantage that the GPS signal is not always available in the rail vehicle and, even when present, does not always produce a usable signal, for example when travelling through tunnels, which may run over long distances in mountainous terrain. Furthermore, there are only restricted transmission and reception capabilities in many networks, such as underground systems, by virtue of the system, and GPS location can therefore be used only to a highly restricted extent.
In order to overcome this problem, another possibility is known from the general prior art for determination of the current position of the rail vehicle, in which inductively acting position marks which are incorporated in the track section directly transmit the information relating to defined waypoints to the rail vehicle.
However, this technical solution also requires additional hardware complexity, which must be planned in during the design of the rail vehicle and of the track section.